John B Keane, who has died aged 73 of prostate cancer, was one of Ireland's most forthright, individualistic and controversial playwrights, with international stage and screen successes such as The Field to his credit.

Born in Listowel, in the heart of Co Kerry, which has always considered itself a kingdom apart, Keane's literary background was similar to that of many other writers whose achievements contributed to "the Listowel phenomenon". His particular skill lay in depicting the close commerce between town and mountain, the tensions between an ostensibly civilised Catholic urbanity and its underlying paganism.

The son of a schoolmaster, Keane left St Michael's College, Listowel, to work, from 1946 to 1951, as a chemist's assistant, a post in which his chief duty was preparing ointment for the Earl of Doneraile's piles. Still embittered by a teacher's hostility to his creative imagination, he took the boat to England, where he had several jobs, among them a furnace operator. Back in Ireland in 1955, he put his meagre savings into buying a public house in Listowel, and settled down to the off-duty task of writing plays rooted in the urban-rural divide of his childhood.

Tinkers, matchmakers, brutal farmers and wily women populate these dramas, which Ernest Blythe, the dictatorial director at Dublin's National (Abbey) Theatre, considered unrepresentative of a peasant society anxious to transform itself into a modern industrial economy.

Nevertheless, Keane's first effort, Sive (1959), a crude drama in the bartered-bride genre, found its way on to the Abbey stage by virtue of winning an amateur competition, the all-Ireland drama festival. The play transformed the so-called peasant drama - with its themes of emigration, the domineering mother, spiritual versus commercial values, adultery and greed for land - and made it comprehensible to metropolitan audiences by anchoring it to everyday realities.

Despite Blythe's declaration that Keane's treatment of some of these themes was "too grotesque for words", Keane found ways to translate them into words that could be heeded by audiences who might otherwise have considered themselves too sophisticated to hear the news from "hidden Ireland". Despite the plentiful attention paid to fellow playwrights Brian Friel and Tom Murphy, critics, however, ignored Keane's work.

The integration of Sive, Big Maggie (1967), and his master piece The Field (1965) into the maintream repertoire of the Abbey, and also of Dublin's commercial theatre, was the vindication of Keane's years of honestly recording, and reflecting on, the evolution of rural Ireland. In 1988, when the Abbey visited Moscow and Leningrad, The Field was chosen in tandem with an adaptation, by Tom Macintyre, of Kavanagh's The Great Hunger.

Altogether, Keane wrote 19 plays, The Year Of The Hiker (1962) and Sharon's Grave (1960) being among the more accomplished. But from the 1980s, he struggled to produce drama which reflected what he regarded as the decline in rural values.

There were many enthusiastic supporters of his work: Siobhan McKenna was an early champion of Sive; Ray MacAnally created the role of Bull McCabe in The Field; while, in 1969, Marie Kean played the title role in Big Maggie- in a cast that included Brenda Fricker, who was brilliantly to recreate it in 1988. The play had a Broadway run in 1982.

Only Richard Harris's por trayal of Bull, in the 1990 film of The Field, was a disappointment. Keane himself was ambivalent about the extensive rewrites, by director Jim Sheridan, which made Bull a much weaker and more vulnerable character than in the original conception. Dramatically, the film pandered to the camera, though the box-office receipts did much to mollify Keane's reservations.

Besides plays, Keane also produced a series of epistolary squibs, such as Letters Of A Successful TD (or member of the Irish parliament) and Letters Of A Love-Hungry Farmer, which ridiculed those who seek respectability in the mistaken belief that they are acquiring dignity. He was a lifelong opponent of unfeeling orthodoxy, and his four novels display compassion for other's suffering, particularly at the hands of those in authority. The Bodhran Makers (1986) portrayed the vivid clash of ultramontane, hardline Catholicism with the spontaneity and freedom of ordinary life.

Keane was a popular figure, who took his public responsibilities seriously. For five years from 1974, he was a member of the Irish Arts Council, and, in 1971, became a founder of the now internationally renowned Listowel Writers' Week.

In 1966, he became involved in the Language Freedom Movement, which sought to put the teaching of Gaelic on a voluntary, rather than a compulsory, basis. His advocacy of the movement involved Keane in several unpleasant situations, and, at one stage, his life was at risk from extremists. He was, however, tenacious in his support for the individual conscience when he felt it was threatened by the dangers of collective willpower. It was a tenacity which, despite eight years of cancer, he maintained to the end of his life.

He is survived by his wife Mary, their daughter and three sons; the broadcaster Fergal Keane is a nephew.

· John Brendan Keane, playwright and novelist, born July 21 1928; died May 30 2002